Scroll compressor

ABSTRACT

An orbiting scroll compressor includes: a frame fixed in a casing; a driving motor fixed in the casing and supplying a driving force; a fixed scroll fixed in the casing; an orbiting scroll forming a first compression space as its one side is interlocked with the fixed scroll, and orbiting by being eccentrically coupled to a driving shaft connected to the driving motor; an orbiting vane protruding from the other side of the orbiting scroll to a predetermined height and forming a second compression space with a vane receiving groove of the frame; a capacity varying unit communicating with the second compression space and varying its capacity; and a control unit connected to the capacity varying unit and controlling the capacity varying unit. Thus, as the orbiting vane is provided, compression performance is improved while maintaining the size of the compressor. Also, because a compression capacity is varied to allow the optimum operation according to external conditions, the efficiency of the compressor can be improved.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a scroll compressor, and particularly,to a scroll compressor to improve compression performance whilemaintaining the size of a compressor and to improve efficiency of thecompressor by varying a compression capacity and thusly allowing theoptimum operation according to external conditions.

2. Description of the Background Art

In general, a compressor converts electric energy into kinetic energyand compresses a refrigerant gas by the kinetic energy. The compressoris a core factor constituting a freezing cycle system, and there arevarious kinds of compressors according to a compression mechanism forcompressing a refrigerant, such as a rotary compressor, a scrollcompressor, a reciprocal compressor and the like. The freezing cyclesystem including such a compressor is being used in a refrigerator, anair conditioner, a showcase and the like.

In the scroll compressor of such compressors, a driving force of adriving motor is transferred to an orbiting scroll, and the orbitingscroll orbits, interlocked with a fixed scroll, thereby continuouslytaking in, compressing and discharging a gas. The orbiting scroll andthe fixed scroll are respectively provided with wraps of an involuteshape, and a plurality of compression pockets are formed by the wrap ofthe fixed scroll and the wrap of the orbiting scroll. As the compressionpockets move toward a discharge hole through which a gas is dischargedby orbiting of the orbiting scroll, their volumes are contracted, andthe gas is compressed.

In general, the compression pockets are formed as a pair symmetricallyon the basis of a discharge hole. The two compression pockets formed asa pair have the same volume. As the pair of compression pockets movetoward the discharge hole by gas taken in from an intake side, anotherpair of compression pockets are formed at the intake side. Suchprocesses are repetitively performed.

FIG. 1 is proposed to describe the structure of the scroll compressor inmore detail. FIG. 1 is a sectional view which illustrates one example ofthe conventional scroll compressor.

As shown, the scroll compressor includes a casing 10 provided with anintake pipe SP and a discharge pipe DP, a main frame 20 and a sub-frame30 fixedly coupled within the casing 10 and spaced apart from each otherat a certain is interval therebetween in a vertical direction, a fixedscroll 40 fixedly coupled to the casing 10 and placed above the mainframe 20, an orbiting scroll 50 positioned between the fixed scroll 40and the main frame 20 and interlocked with the fixed scroll 40 to orbit,an oldham ring 60 positioned between the orbiting scroll 50 and the mainframe 20 and preventing rotation of the orbiting scroll 50, a drivingmotor 100 fixedly coupled to the casing 10, placed between the mainframe 20 and the sub-frame 30 and generating a driving force, a rotaryshaft 70 transferring the driving force of the driving motor 100 to theorbiting scroll 50, and a valve assembly 80 mounted on the fixed scroll40.

The main frame 20 includes a shaft insertion hole 22 formed at a framebody portion 21 having a predetermined shape, in which the rotary shaft70 is penetratingly inserted, a boss insertion groove 23 connected tothe shaft insertion hole 22 and having an inner diameter greater thanthat of the shaft insertion hole 22, and a bearing surface 24 formed atan upper surface of the frame body portion 21, at which the orbitingscroll 50 is supported.

The fixed scroll 40 includes a body portion 41 having a predeterminedshape, a wrap 42 having an involute shape and formed at one surface ofthe body portion 41 with a certain thickness and length, a dischargehole 43 penetratingly formed at the center of the body portion 41 and anintake hole 44 formed at one side of the body portion 41.

The orbiting scroll 50 includes a circular plate 51 having a certainthickness and area, a wrap 52 having an involute shape and formed at onesurface of the circular plate 51 with a certain thickness and height, aboss portion 53 protrudingly formed to a certain height at the center ofthe other surface of the circular plate 51, and a shaft insertion groove54 formed inside the boss portion 53 to a certain depth, in which partof the rotary shaft 70 is inserted.

The orbiting scroll 50 forms a compression pocket (P) such that its wrap52 is interlocked with the wrap 42 of the fixed scroll 40, and the bossportion 53 of the orbiting scroll 50 is inserted in the boss insertiongroove 23 of the main frame 20. The circular plate 51 of the orbitingscroll 50 is coupled between the fixed scroll 40 and the main frame 20such that one surface of the circular plate 51 is supported at thebearing surface 24 of the main frame.

The rotary shaft 70 includes a shaft portion 71 having a certain length,an eccentric portion 72 extending from one side of the shaft portion 71to a certain length to be eccentric from the center of the shaft portion71, and an oil path 73 penetratingly formed at the shaft portion 71 andthe eccentric portion 72.

The shaft portion 71 of the rotary shaft 70 is coupled to the drivingmotor 100. One side of the shaft portion 71 of the rotary shaft ispenetratingly inserted in the shaft insertion hole 22 of the main frame20, and its eccentric portion 72 is inserted in the shaft insertiongroove 54 of the orbiting scroll.

An eccentric bush 90 having a predetermined shape is inserted in theeccentric portion 72 of the rotary shaft 70, and a fixed bush 92 whichslidingly comes into contact with the eccentric bush 90 is fixedlycoupled to an inner wall of the shaft insertion groove 54 of theorbiting scroll.

Oil is filled at a lower portion of the casing 10.

Undescribed reference numeral 110 is a stator, 120 is a rotor, 130 is abalance weight, 140 is an oil feeder, 150 is a discharge cover and S isa discharge space.

The operation of the scroll compressor will now be described.

When power is applied to a scroll compressor, a rotary force isgenerated from the driving motor 100 by the operation of the drivingmotor 100 and is transferred to the orbiting scroll 50 through therotary shaft 70. As the rotary force of the rotary shaft 70 istransferred to the orbiting scroll 50, the orbiting scroll 50 coupled tothe eccentric portion 72 of the rotary shaft orbits about an axis of therotary shaft 70. Because the rotation of the orbiting scroll 50 isprevented by the oldham ring 60, the orbiting scroll 50 can orbit.

As the wrap 52 of the orbiting scroll orbits, interlocked with the wrap42 of the fixed scroll by the orbiting of the orbiting scroll 50, aplurality of compression pockets (P) formed by the wrap 52 of theorbiting scroll and the wrap 42 of the fixed scroll move toward acentral portion of the fixed scroll 40 and the orbiting scroll 50,changing their volumes. Thusly, a gas is taken in, compressed and thenis discharged through the discharge hole 43 of the fixed scroll.

The oil filled in the lower portion of the casing flows through the oilpath 73 of the rotary shaft by the rotation of the rotary shaft 70,thereby being supplied to components that slide.

According to the rotation of the rotary shaft 70, the eccentric portion72 of the rotary shaft rotates, wherein a radius of the rotation of theeccentric portion 72 is an eccentric distance between the eccentricportion 72 and the center of the shaft portion 71 of the rotary shaft.The rotation of the eccentric portion 72 of the rotary shaft istransferred to the boss portion 53 of the orbiting scroll, so that theorbiting scroll 50 orbits. The eccentric bush 90 inserted in theeccentric portion 72 prevents direct friction between the eccentricportion 72 of the rotary shaft and the boss portion 53 of the orbitingscroll, and stably maintains the rotation of the rotary shaft 70.

In case of the air conditioner employing the freezing cycle systemhaving such a compressor, it is required to vary a capacity of thecompressor in order to reduce power consumption of the air conditioneraccording to the changing weather.

As a conventional mechanism for varying the capacity of the compressor,a method of controlling revolutions of the driving motor constitutingthe compressor is being used. However, if an inverter is used therefor,a unit cost of manufacture can be increased because the inverter isnormally expensive. For this reason, there is a need to implementcapacity variation while a constant speed motor which is relativelycheap is used.

Also, a method of bypassing a gas is being used as another mechanism ofthe conventional art. However, this method is disadvantageous in thatthe capacity cannot be varied variously.

SUMMARY OF THE INVENTION

Therefore, an object of the present invention is to provide a scrollcompressor to improve compression performance while maintaining the sizeof the compressor and to improve efficiency of the compressor by varyinga compression capacity and thusly allowing the optimum operationaccording to external conditions.

To achieve these and other advantages and in accordance with the purposeof the present invention, as embodied and broadly described herein,there is provided an orbiting scroll compressor comprising: a framefixed in a casing; a driving motor fixed in the casing and supplying adriving force; a fixed scroll fixed in the casing; an orbiting scrollforming a first compression space as its one side is interlocked withthe fixed scroll, and orbiting by being eccentrically coupled to adriving shaft connected to the driving motor; an orbiting vaneprotruding from the other side of the orbiting scroll to a predeterminedheight and forming a second compression space with a vane receivinggroove of the frame; a capacity varying unit communicating with thesecond compression space and varying its capacity; and a control unitconnected to the capacity varying unit and controlling the capacityvarying unit.

The foregoing and other objects, features, aspects and advantages of thepresent invention will become more apparent from the following detaileddescription of the present invention when taken in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute aunit of this specification, illustrate embodiments of the invention andtogether with the description serve to explain the principles of theinvention.

In the drawings:

FIG. 1 is a longitudinal sectional view which illustrates part of theconventional scroll compressor;

FIG. 2 is a block diagram of a freezing cycle system including a scrollcompressor in accordance with the present invention;

FIG. 3 is a longitudinal sectional view which illustrates one example ofthe scroll compressor in accordance with the present invention;

FIG. 4 is a plan view which illustrates a capacity varying apparatus fora vane compression unit of the scroll compressor in accordance with thepresent invention;

FIG. 5 is an exploded plan view which illustrates the capacity varyingapparatus of the scroll compressor in accordance with the presentinvention;

FIGS. 6A to 6D are schematic views showing the compression principle ofthe scroll compressor in accordance with the present invention;

FIGS. 7A and 7B are schematic views of the operation of the capacityvarying apparatus of the scroll compressor in accordance with thepresent invention;

FIG. 8 is a longitudinal sectional view which illustrates a modifiedexample of the scroll compressor in accordance with the presentinvention;

FIG. 9 is a plan view which illustrates a modified example of thecapacity varying apparatus for the vane compression unit of the scrollcompressor in accordance with the present invention; and

FIGS. 10A to 10C are schematic views which illustrate the operation ofthe modified capacity varying apparatus of the scroll compressor inaccordance with the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference will now be made in detail to the preferred embodiments of thepresent invention, examples of which are illustrated in the accompanyingdrawings.

FIG. 2 is a block diagram of a freezing cycle system including a scrollcompressor in accordance with the present invention, FIG. 3 is alongitudinal sectional view which illustrates one example of the scrollcompressor in accordance with the present invention, FIG. 4 is a planview which illustrates a capacity varying apparatus for a vanecompression unit of the scroll compressor in accordance with the presentinvention, FIG. 5 is an exploded plan view which illustrates thecapacity varying apparatus of the scroll compressor in accordance withthe present invention, FIG. 6 is a schematic view for describing acompression principle of the scroll compressor in accordance with thepresent invention, and FIGS. 7A and 7B are schematic views of theoperation of the capacity varying apparatus of the scroll compressor inaccordance with the present invention.

As shown, the scroll compressor in accordance with the present inventionincludes a casing 1 provided with a gas intake pipe (SP) and a gasdischarge pipe (DP), a main frame 10 and a sub-frame (not shown)respectively fixed to upper and lower sides of an inner circumferentialsurface of the casing 1, a driving motor 3 mounted between the mainframe 10 and the sub-frame (not shown), a driving shaft 4 pressinglyinserted in the center of the driving motor 3, penetrating the mainframe 10 and transferring a rotary force of the driving motor 3, a fixedscroll 20 fixedly installed at an upper surface of the main frame 10, anorbiting scroll 30 placed on the main frame 10 and interlocked with thefixed scroll 20 to orbit, so that two scroll type compression pockets(hereinafter, referred to as “first compression pockets”) are formed asa pair, an oldham ring 40 installed between the orbiting scroll 30 andthe main frame 10 and preventing rotation of the orbiting scroll 30 toallow the orbiting of the orbiting scroll 30, a sliding block 50 coupledto a rear side of the orbiting scroll 30, sliding in a radial directionand forming a plurality of vane type compression pockets (hereinafter,referred to as “second compression pockets”) P21 and P22 between a vanereceiving groove 14 of the main frame 10 and an orbiting vane 33 of theorbiting scroll 30 which are to be described later, a discharge cover 8coupled to a rear side of the fixed scroll 20 and dividing the inside ofthe casing 1 into an intake space S1 and a discharge space (S2), acapacity varying unit 60 (FIG. 5) provided at the main frame and varyingthe capacity of the second compression pockets, and a control unit 70connected to the capacity varying unit 60 and operating the capacityvarying unit 60 by a pressure difference according to an operation modeof the compressor.

As shown in FIGS. 3 to 5, a shaft hole 11 supporting the driving shaft 4in a radial direction is formed at the center of the main frame 10, anda boss receiving groove 12 is extendingly formed at an upper portion ofthe shaft hole 11 to allow an orbiting movement of a boss portion 32 ofthe orbiting scroll 30. Also, a vane receiving groove 14 is formedoutside the boss receiving groove 12 and forms the second compressionpocket P2 such that orbiting vanes 33 to be described later are insertedtherein, having therebetween a partition wall 13 of a predeterminedthickness. Also, a vane-side intake hole 15 and a plurality of vane-sidedischarge holes 16 a and 16 b are formed on a bottom surface of the vanereceiving groove 14, having the sliding block 50 therebetween. On thebasis of the sliding block 50, the vane-side intake hole 15 is formed atone side of a circumferential direction and, at the other side thereof,the plurality of vane-side discharge holes 16 a are formed outside andinside the orbiting vane 33 to be described later, respectively. Themiddle portion of the vane-side intake hole 15 and the middle portion ofthe vane-side discharge hole 16 a communicate with each other, and suchcommunication therebetween is allowed or blocked by a sliding valve 61to be described later, which is formed within a bypass hole 17. Here,the vane receiving groove 14 may have the same depth as that of the bossreceiving groove 12. However, as occasion demands, the boss receivinggroove 12 may have the greater depth to form an oil discharge hole in aradial direction.

As shown in FIG. 5, the compression pocket can be divided into an outervane type compression pocket (outer pocket) P21 and an inner vane typecompression pocket (inner pocket) P22 by the orbiting vane 33, and avane-side intake hole 15 is formed to have an area that allowscommunication with the outer pocket P21 or the inner pocket P22 or bothduring operation. Also, vane-side discharge holes 16 a, 16 b arepreferably formed apart from each other with a spaced interval betweeneach discharge hole 16 a, 16 b, whereby each discharge hole 16 a, 16 bis formed to have an area that allows communication with the outerpocket P21 and the inner pocket P22, respectively. Also, the vane-sideintake hole 15 and the vane-side discharge holes 16 a and 16 b penetratethe inside of the main frame 10, wherein, preferably, the vane-sideintake hole 15 communicates with the intake space S1 of the casing 1 andthe vane-side discharge holes 16 a and 16 b communicate with thedischarge space S2 of the discharge cover 8 through the main frame 1 andthe fixed scroll 20. Here, discharge valves (not shown) are installed atoutlet ends of the vane-side discharge holes 16 a and 16 b in order tocontrol the discharge operation of a refrigerant gas from bothcompression pockets P21 and P22.

The bypass hole 17 is formed to a predetermined depth to perpendicularlypenetrate the vane-side intake hole 15 and the vane-side discharge hole16 a from an outer circumferential surface of the main frame 10, and itsopened one side is sealed by a valve stopper 63 pressingly insertedthereinto and having a back pressure through hole 63 a and. A uniformhole 18 is formed at a circumferential surface of a space where a valvespring 62 to be described later is installed so as to communicate withthe intake space S1.

The fixed scroll 20 includes a wrap 21 having an involute shape andforming a pair of first compression pockets P1 by being interlocked witha wrap 31 of the orbiting scroll 30. Also, the fixed scroll 20 includesa scroll-side intake hole 22 formed outside the outermost wrap, and ascroll-side discharge hole 23 formed at the center portion of the fixedscroll 20 and communicating with the discharge space S2 of the casing 1.

As shown in FIGS. 3 and 4, the orbiting scroll 30 includes a wrap 31having an involute shape and interlocked with the wrap 21 of the fixedscroll 20, a boss portion 32 formed at the center of a lower surface ofthe circular plate, coupled to an eccentric portion of the driving shaft4 and orbiting within the boss receiving pocket 12 of the main frame 10,and an annular orbiting vane 33 formed outside the boss portion 32 at apredetermined interval therebetween such that, when the orbiting scroll30 orbits, its outer circumferential surface comes in line-contact withan inner circumferential surface of the boss receiving groove 12 and itsinner circumferential surface comes in line-contact with an outercircumferential surface of the partition wall 13 of the main frame 10. Ablock slit 33 a is formed at one side of a circumferential surface ofthe orbiting vane 33, namely between the vane-side intake hole 15 andtwo vane-side discharge holes 16 a and 16 b so that the sliding block 50can slide in a radial direction.

As shown in FIG. 4, as for the sliding block 50, its outercircumferential surface is formed as a circular arc shape so as toslidingly contact with an outer circumferential surface of the vanereceiving groove 14 of the main frame 10, and its inner circumferentialsurface is formed as a circular arc shape so as to slidingly contactwith an outer circumferential surface of the partition wall 13 of themain frame 10, which constitutes an inner circumferential surface of thevane receiving groove 14. Such a construction of the sliding block 50 ispreferable to prevent a leakage of a refrigerant gas.

As shown in FIG. 5, the capacity varying unit 60 includes a slidingvalve 61, slidingly inserted in the bypass hole 17, that opens andcloses the vane-side intake hole 15 and the vane-side discharge hole 16a by moving within the bypass hole 17 according to a pressure differencedue to the control unit 70, at least one valve spring 62 including acompression spring elastically supporting a moving direction of thesliding valve 61 so as to move the sliding valve 61 to a position wherethe sliding valve 61 is closed when there is no pressure differencebetween both ends, and a valve stopper 63 shielding an opened end of oneside of the bypass hole 17 so as to prevent escape of the sliding valve61.

The sliding valve 61 includes a first pressure portion 61 a slidinglycoming in contact with an inner circumferential surface of the bypasshole 17 and receiving pressure from the control unit 70, a secondpressure portion 61 b slidingly coming in contact with a circumferentialsurface of the bypass hole 17, supported by the valve spring 62 andallowing and blocking communication between the vane-side intake hole 15and the vane-side discharge hole 16 a, and a communication portion 61 cconnecting the two pressure portions 61 a and 61 b and forming a gaspath between its outer circumferential surface and the bypass hole 17.Preferably, for the purpose of minimizing a length of the valve, thesecond pressure portion 61 b have a smaller diameter than diameters ofthe vane-side intake hole 15 and the vane-side discharge hole 16 a and aspring fixing groove (not shown) in which the valve spring 62 isinserted to be fixed is formed at the inside of a rear end of the secondpressure portion 61 b.

As described above, the valve spring 62 may be installed at a rearsurface of the second pressure portion 61 b that allows or blockscommunication between the vane-side intake hole 15 and the vane-sidedischarge hole 16 a. However, as occasion demands, the valve spring 62may be installed at a rear surface of the first pressure part 61 a, anda common connection pipe 74 of the control unit 70 to be described latermay be installed at the rear surface of the second pressure portion 61 bto communicate therewith.

A back pressure through hole 63 a is formed at the center of the valvestopper 63 and is connected to the common connection pipe 74 of thecontrol unit 70 to be described later.

As shown in FIGS. 4 and 5, the control unit 70 includes a switchingvalve assembly 71 determining pressure of the pressure portion side ofthe sliding valve 61, a high pressure connection pipe 72 connectedbetween the gas discharge pipe (DP) and a high pressure side inlet 75 aof the switching valve assembly 71 and supplying a high pressureatmosphere, a low pressure connection pipe 73 connected between the gasintake pipe (SP) and a low pressure side inlet 75 b of the switchingvalve assembly 71 and supplying a low pressure atmosphere, and a commonconnection pipe 74 connecting a common side outlet 75 c of the switchingvalve assembly 71 to the back pressure through hole 63 a of the valvestopper 63 and selectively supplying the high pressure atmosphere or thelow pressure atmosphere to the first pressure portion 61 a of thesliding valve 61.

The switching valve assembly 71 includes a switching valve housing 75having the high pressure side inlet 75 a, the low pressure side inlet 75b and the common side outlet 75 c, a switching valve 76 slidinglycoupled to the inside of the switching valve housing 75 to selectivelyconnect the high pressure side inlet 75 a to the common side outlet 75 cor the low pressure side inlet 75 b to the common side outlet 75 c, anelectromagnet installed at one side of the switching valve housing 75and moving the switching valve 76 by applied power, and a switchingvalve spring 78 returning the switching valve 76 to an initial positionwhen the power applied to the electromagnet 77 is cut off.

On the drawing, undescribed reference mark A1 is a condenser, A2 is aexpansion mechanism, A3 is an evaporator, 3A is a stator, 19 is a keygroove, and 41, 43 and 44 are a body portion, an upper key portion and asliding surface of the oldham ring, respectively.

The same reference marks are designated to the same parts as those ofthe conventional art.

The capacity varying apparatus of the scroll compressor in accordancewith the present invention has the following operational effect.

As shown in FIG. 3, as the driving shaft 4 is rotated together with arotor 3B of the driving motor 3 by applied power, the orbiting scroll 30orbits as long as an eccentric distance to thereby form a pair of firstcompression pockets P1 between the wrap 31 of the orbiting scroll 30 andthe wrap 21 of the fixed scroll 20. The first compression pockets P1continuously move toward the center by the continuous orbiting of theorbiting scroll 30, contracting the volumes. In such a process, arefrigerant gas is received in the first compression pockets P1 throughthe scroll-side intake hole 22 from the intake space S1 of the casing 1,is gradually compressed, and then is discharged to the discharge spaceS2 of the casing 1 through the scroll-side discharge hole 23 of thefixed scroll 20.

Also, as shown in FIGS. 4 and 5, because the orbiting vane 33 is formedat a rear surface of the orbiting scroll 30 and the sliding block 50linearly moving in a radial direction is provided at the orbiting vane33 between the vane-side intake hole 15 and each vane-side dischargehole 16 a, 16 b, when the orbiting scroll orbits 30, an outer pocket P21and an inner pocket P22 are formed with a phase difference of 180°therebetween by the sliding block between an outer circumferentialsurface of the orbiting vane 33 of the orbiting scroll 30 and an innercircumferential surface of the boss receiving groove 12 of the mainframe 10 and between an inner circumferential surface of the orbitingvane 33 and an outer circumferential surface of the partition wall 13 ofthe main frame 10, respectively. Thus, the refrigerant gas within thecasing 1 is received alternately in the outer pocket (P21) and the innerpocket (P22) through the vane-side intake hole 15, is compressedtherein, and then is discharged through both vane-side discharge holes16 a and 16 b. The discharged gas is discharged to the discharge space(S2) of the casing through a gas guiding pipe (not shown) or a gasthrough hole (not shown), and is discharged to the gas discharge pipe(DP) of the casing 1 together with the compressed gas discharged fromthe first compression pocket (P1).

Here, the process in which a refrigerant is received and compressed inthe second compression pocket will now be described in more detail.

For example, as shown in FIG. 6A, when the block slit 33 a of theorbiting vane 33 aligns with the outer circumferential surface of thesliding block 50 while contacting with the inner circumferential surfaceof the vane receiving groove 14 of the main frame 10, if this situationis assumed to be 0 degrees, the intake hole 15 is only in communicationwith the inner pocket P22 at one side of the sliding block 50 to allowintake of a refrigerant therethrough, while simultaneously, at the otherside of the sliding block 50, the discharge operation begins. Meanwhile,at the outer pocket P21, intake is completed and the compressionoperation begins.

Then, as shown in FIG. 6B, when the orbiting vane 33 reaches a positionof 90 degrees by orbiting further, the intake of a refrigerant is finelyperformed through the outer pocket P21 at one side of the sliding block50, while simultaneously, at the other side of the sliding block 50, thecompression is further performed therethrough. Meanwhile, in the innerpocket (P22), as an intake area gets greater, the intake of therefrigerant is performed at its one side, while simultaneously, at theother side thereof, the compression is terminated.

Then, as shown in FIG. 6C, when the orbiting vane 33 reaches a positionof 180 degrees by orbiting further, the intake is performed at one sideof the outer pocket P21, while simultaneously, at the other side of theouter pocket P21, the discharge begins. Meanwhile, at the inner pocketP22, the intake is completed and the compression operation begins.

Then, as shown in FIG. 6D, when the orbiting vane 33 reaches a positionof 270 degrees by orbiting further, the intake of the refrigerant iscontinuously performed at one side of the outer pocket P21, whilesimultaneously, at the other side of the outer pocket P21, thecompression is completed. Also, the intake begins at one side of theinner pocket P22 and the compression continues at the other sidethereof. Then, the stroke described through FIGS. 6A through 6D isrepetitively performed.

The scroll compressor using a vane type compression method is operatedin a high capacity mode or a low capacity mode according to an operationstate of an air conditioner employing such a compressor, and this willnow be described in more detail.

First, as shown in FIG. 7A, in the high-capacity operation mode, aspower is applied to the electromagnet 77 of the control unit 70 which isa a pilot valve, the switching valve 76 overcomes an elastic force ofthe switching valve spring 78 and moves to allow communication betweenthe low pressure side outlet 75 b and the common side outlet 75 c. Then,a low pressure refrigerant gas having passed through the gas intake pipe(SP) or the evaporator (A3) is introduced toward the first compressionportion 61 a of the sliding valve 61 via the low pressure connectionpipe 73 and the common connection pipe 74. Here, the sliding valve 61 ispushed by the elastic force of the valve spring 62 supporting the secondpressure portion 61 and is thusly moved to the right side of thedrawing, so that the second pressure portion 61 b is placed between thevane-side intake hole 15 and the vane-side discharge hole 16. In such amanner, the refrigerant gas having received in the outer pocket (P21)and the inner pocket (P22) is completely compressed, then, is dischargedto the discharge space (S2) of the discharge cover 8, and circulatesthrough the condenser (A1), the expanding mechanism (A2) and theevaporator (A3), thereby performing a compression operation thatexhibits approximately 100% cooling capability.

In contrast, as shown in FIG. 7B, in the low-capacity operation, aspower is not applied to the electromagnet 77 of the control unit 70which is a pilot valve, the switching valve 76 is moved by the elasticforce of the switching valve spring 78 to thereby allow communicationbetween the high pressure outlet 75 a and the common side outlet 75 c.Thus, a high pressure refrigerant gas within the gas discharge pipe (DP)or the casing 1 is introduced toward the first pressure portion 61 a ofthe sliding valve 61 via the high pressure connection pipe 72 and thecommon connection pipe 74. Here, the sliding valve 61 overcomes anelastic force of the valve spring 62 by the high pressure atmosphereformed at a pressure surface of the first pressure portion 61 a, and ismoved to the right side of the drawing, so that the communicationportion 61 c of the sliding valve 61 is placed between the vane-sideintake hole 15 and the vane-side discharge hole 16, allowingcommunication between the intake hole 15 and the discharge hole 15 a. Insuch a manner, a refrigerant gas having received in the outer pocket(P21) of the second compression pocket (P2) is leaked to the vane-sideintake hole 15 through the vane-side discharge hole 16 a and the bypasshole 17. For this reason, the compression does not occur in the outerpocket (P21) of the second compression pocket (P2) but occurs only inthe inner pocket (P22) of the second compression pocket (P2).

Here, if the valve spring of the capacity varying unit is installed at arear surface of the first pressure portion of the sliding valve, thecontrol unit moves the sliding valve in an opposite manner to thatdescribed above to achieve the high-capacity operation and thelow-capacity operation. Because the operation of the capacity varyingunit is the same as that of the aforementioned one, the detaileddescription thereon will be omitted.

As the scroll compressor includes a vane compression part besides ascroll compression part, the capacity thereof can be greatly improvedwithout increasing the size of the compressor. Also, because thecapacity of the vane compression part is varied into two levels, thecapacity varying performance of the scroll compressor can be improved.

Also, the scroll compressor in accordance with the present invention maybe operated not only in the high-capacity operation mode and thelow-capacity operation mode but also in a medium-capacity operationmode. In such a case, preferably, the capacity of an outer pocket of thesecond compression pocket is different from the capacity of an innerpocket. The case where the capacity of the outer pocket is set to 60%and the capacity of the inner pocket is set to 40% will now be describedas an example.

FIG. 8 is a longitudinal sectional view which illustrates a modifiedexample of the scroll compressor in accordance with the presentinvention, FIG. 9 is a plan view which illustrates a modified example ofthe capacity varying apparatus for the vane compression unit of thescroll compressor in accordance with the present invention, and FIGS.10A to 10C are schematic views which illustrate the operation of themodified capacity varying apparatus of the scroll compressor inaccordance with the present invention.

As shown, the vane compression part of the scroll compressor inaccordance with the present invention includes: a main frame 10including a first vane-side intake hole 15 a and a first vane-sidedischarge hole 16 a that are in communication with the aforementionedouter pocket (P21), a second vane-side intake hole 15 b and a secondvane-side discharge hole that are in communication with the inner pocket(P22), a first bypass hole 17 a formed to allow communication betweenthe first vane-side intake hole 15 a and the first vane discharge hole16 a, and a second bypass hole 17 b formed to allow communicationbetween the second vane-side intake hole 15 b and the second vanedischarge hole 16 b; a first capacity varying unit 60 for varying acapacity of the outer pocket (P21) by opening or closing the firstbypass hole 17 a of the main frame 10; a first control unit 70 fordriving the first capacity varying unit 60; a second capacity varyingunit 80 for varying a capacity of the inner pocket (P22) by opening orclosing the second bypass hole 17 b of the main frame 10; and a secondcontrol unit 90 for driving the second capacity varying unit 80.

Because the first capacity varying unit 60, the second capacity varyingunit 80, the first control unit 70 and the second control unit 90 arethe same as those that were described in one example with reference toFIGS. 4 and 5, the detailed description thereon will be omitted.

The same reference numerals are designated to the same parts as thosethat were described in one example.

Undescribed reference numerals 61 and 81 are first and second slidingvalves, 61 a and 81 a are first pressure portions of sliding valves, 61b and 81 b are second pressure portions of the sliding valves, 61 c and81 c are communication portions of the sliding valves, 62 and 82 arefirst and second valve springs, 63 and 83 are first and second valvestoppers, 71 and 91 are first and second switching valve assemblies, 72and 92 are first and second high-pressure connection pipes, 73 and 93are first and second low-pressure connection pipes, 74 and 94 are firstand second common connection pipes, 75 and 95 are first and secondswitching valve housings, 76 and 96 are first and second switchingvalves, 77 and 97 are first and second electromagnets, and 78 and 98 arefirst and second switching valve springs.

The scroll compressor in accordance with the present invention have thefollowing operational effect.

First, in the high-capacity operation mode, as shown in FIG. 10A, by thefirst control unit 70 and the second control unit 90, the secondpressure portions 61 b and 81 b of the sliding valves 61 and 81 blockcommunication between the vane-side intake holes 15 a and 15 b and thevane-side discharge holes 16 a and 16 b, respectively. Thusly, arefrigerant having received in the outer pocket (P21) and the innerpocket (P22) of the second compression pocket (P2) is completelycompressed and discharged, so that the vane compression part of thescroll compressor exhibits 100% cooling capability.

Then, in the medium-capacity operation mode, as shown in FIG. 10B, bythe first control unit 60, the second pressure portion 61 b of the firstsliding valve 61 blocks the communication between the first vane-sideintake hole 15 a and the first vane-side discharge hole 16 a, so thatthe refrigerant having received in the outer pocket (P21) is completelycompressed and discharged. Meanwhile, by the second control unit 70, thecommunication portion 81 c of the second sliding valve 81 is placedbetween the second vane-side intake hole 15 b and the second vane-sidedischarge hole 16 b, so that a refrigerant having received in the innerpocket (P22) is not compressed but leaked. Thus, the vane compressionpart of the scroll compressor exhibits only 60% cooling capability whichis same as the capacity of the outer pocket (P21).

Then, in the low-capacity operation mode, as shown in FIG. 10C, by thefirst control unit 71, the communication portion 61 c of the firstsliding valve 61 is placed between the first vane-side intake hole 15 aand the first vane-side discharge hole 16 a, so that the refrigeranthaving received in the outer pocket (P21) is not compressed but leaked.Meanwhile, by the second control unit 90, the second pressure portion 81b of the second sliding valve 81 blocks the communication between thesecond vane-side intake hole 15 b and the second vane-side dischargehole 16 b, so that the refrigerant having received in the inner pocket(P22) is completely compressed and discharged. Thus, the vanecompression part of the scroll compressor exhibits 40% coolingcapability which is the same as the capacity of the inner pocket (P22).

In such a manner, by varying the capacity of the vane compression partinto three levels, the capacity varying performance of the scrollcompressor can be more improved.

As described so far, because the scroll compressor in accordance withthe present invention includes a vane compression part besides a scrollcompression part, the capacity of the compressor can be greatlyincreased without increasing the size of the compressor. Also, becausethe capacity of the vane compression part is varied into multiplelevels, the capacity varying performance of the scroll compressor isimproved and the performance of the compressor itself is thusly greatlyimproved.

As the present invention may be embodied in several forms withoutdeparting from the spirit or essential characteristics thereof, itshould also be understood that the above-described embodiments are notlimited by any of the details of the foregoing description, unlessotherwise specified, but rather should be construed broadly within itsspirit and scope as defined in the appended claims, and therefore allchanges and modifications that fall within the metes and bounds of theclaims, or equivalence of such metes and bounds are therefore intendedto be embraced by the appended claims.

1. An orbiting scroll compressor comprising: a frame fixed in a casing;a driving motor fixed in the casing and supplying a driving force; afixed scroll fixed in the casing; an orbiting scroll forming a firstcompression space as its one side is interlocked with the fixed scroll,and orbiting by being eccentrically coupled to a driving shaft connectedto the driving motor; an orbiting vane protruding from the other side ofthe orbiting scroll to a predetermined height and forming a secondcompression space with a vane receiving groove of the frame; a capacityvarying unit communicating with the second compression space and varyingits capacity; and a control unit connected to the capacity varying unitand controlling the capacity varying unit.
 2. The scroll compressor ofclaim 1, wherein the orbiting scroll includes a boss portion formed at arear surface contacting with the frame and eccentrically coupled withthe driving shaft, the orbiting scroll having the orbiting vaneintegrally formed outside the boss portion, and the frame includes aboss receiving groove formed at a central portion of an upper surface onwhich the orbiting scroll and coupled to the orbiting scroll to alloworbiting of the orbiting scroll, and a vane receiving groove formedoutside the boss receiving groove and coupled to the orbiting vane ofthe orbiting scroll to allow the orbiting of the orbiting scroll andthusly form a vane type compression pocket.
 3. The scroll compressor ofclaim 2, wherein a plurality of vane discharge holes are independentlyprovided outside and inside the orbiting vane to thereby form aplurality of vane type compression pockets.
 4. The scroll compressor ofclaim 3, wherein one vane-side intake hole is formed on a bottom surfaceof the vane receiving groove to communicate with the plurality of vanetype compression pockets formed inside and outside the orbiting vane,and one bypass hole is formed to connect a middle portion of thevane-side intake hole with a middle portion of one of the vane-sidedischarge holes and is opened and closed by the capacity varying unit.5. The scroll compressor of claim 3, wherein a plurality of vane-sideintake holes are formed on a bottom surface of the vane receiving grooveto independently communicate with the plurality of vane type compressionpockets formed inside and outside the orbiting vane, and a plurality ofbypass holes are formed to independently connect middle portions of thevane-side intake holes with middle portions of the vane-side dischargeholes and are independently opened and closed by the capacity varyingunit.
 6. The scroll compressor of claim 4, wherein the plurality of vanetype compression pockets formed inside and outside the orbiting vanehave the same capacity.
 7. The scroll compressor of claim 5, wherein theplurality of vane type compression pockets formed inside and outside theorbiting vane have the same capacity.
 8. The scroll compressor of claim4, wherein the plurality of vane type compression pockets formed insideand outside the orbiting vane have different capacities.
 9. The scrollcompressor of claim 5, wherein the plurality of vane type compressionpockets formed inside and outside the orbiting vane have differentcapacities.
 10. The scroll compressor of claim 4, wherein the capacityvarying unit includes a sliding valve slidingly inserted in the bypasshole and opening and closing the vane-side intake hole and the vane-sidedischarge hole by moving by a pressure difference due to the controlunit, and at least one valve spring elastically supporting a movingdirection of the sliding valve and moving the sliding valve to its closeposition when there is no pressure difference between both ends.
 11. Thescroll compressor of claim 5, wherein the capacity varying unit includesa sliding valve slidingly inserted in the bypass hole and opening andclosing the vane-side intake hole and the vane-side discharge hole bymoving by a pressure difference due to the control unit, and at leastone valve spring elastically supporting a moving direction of thesliding valve and moving the sliding valve to its closed position whenthere is no pressure difference between both ends.
 12. The scrollcompressor of claim 10, wherein the sliding valve includes a pluralityof pressure portions placed at both sides of the bypass hole andslidingly contacting with an inner circumferential surface of the bypasshole, wherein at least one pressure portion can allow and blockcommunication between the vane-side intake hole and the vane-sidedischarge hole by moving upon receiving pressure through the controlunit, and a communication portion connecting the plurality of pressureportions and having a gas path between its outer circumferential surfaceand the bypass hole to allow the vane-side intake hole and the vane-sidedischarge hole to communicate with each other.
 13. The scroll compressorof claim 11, wherein the sliding valve includes a plurality of pressureportions placed at both sides of the bypass hole and slidinglycontacting with an inner circumferential surface of the bypass hole,wherein at least one pressure portion can allow and block communicationbetween the vane-side intake hole and the vane-side discharge hole bymoving upon receiving pressure through the control unit, and acommunication portion connecting the plurality of pressure portions andhaving a gas path between its outer circumferential surface and thebypass hole to allow the vane-side intake hole and the vane-sidedischarge hole to communicate with each other.
 14. The scroll compressorof claim 12, wherein the bypass hole includes at at least one of bothsides, a back pressure through hole communicating with an outlet of thecontrol unit.
 15. The scroll compressor of claim 13, wherein the bypasshole includes at at least one of both sides, a back pressure throughhole communicating with an outlet of the control unit.
 16. The scrollcompressor of claim 14, wherein the valve spring is installed at a rearsurface of a pressure portion close to the vane-side discharge hole ofthe sliding valve.
 17. The scroll compressor of claim 15, wherein thevalve spring is installed at a rear surface of a pressure portion closeto the vane-side discharge hole of the sliding valve.
 18. The scrollcompressor of claim 15, wherein the valve spring is installed at a rearsurface of a pressure portion close to the vane-side intake hole of thesliding valve.
 19. The scroll compressor of claim 4, wherein the controlunit includes a switching valve assembly determining pressure of apressure portion side of the sliding valve, a high pressure connectionpipe connected to a high pressure side inlet of the switching valveassembly and providing a high-pressure atmosphere, a low-pressureconnection pipe connected to a low pressure side inlet of the switchingvalve assembly and providing a low-pressure atmosphere, and a commonconnection pipe connecting a common side outlet of the switching valveassembly to the bypass hole and providing a high-pressure atmosphere ora low-pressure atmosphere to a pressure portion of the sliding valve.20. The scroll compressor of claim 5, wherein the control unit includesa switching valve assembly determining pressure of a pressure portionside of the sliding valve, a high pressure connection pipe connected toa high pressure side inlet of the switching valve assembly and providinga high-pressure atmosphere, a low-pressure connection pipe connected toa low pressure side inlet of the switching valve assembly and providinga low-pressure atmosphere, and a common connection pipe connecting acommon side outlet of the switching valve assembly to the bypass holeand providing a high-pressure atmosphere or a low-pressure atmosphere toa pressure portion of the sliding valve.
 21. The scroll compressor ofclaim 19, wherein the switching valve assembly includes a switchingvalve housing including the high-pressure side inlet, the low-pressureside inlet and the common side outlet, a switching valve slidlinglycoupled to the inside of the switching valve assembly and selectivelyconnecting the high-pressure side inlet to the common side outlet or thelow-pressure side inlet to the common side outlet, an electromagnetinstalled at one side of the switching valve housing and moving theswitching valve by applied power, and an elastic member returning theswitching valve to an initial position when power being applied to theelectromagnet is cut off.
 22. The scroll compressor of claim 20, whereinthe switching valve assembly includes a switching valve housingincluding the high-pressure side inlet, the low-pressure side inlet andthe common side outlet, a switching valve slidlingly coupled to theinside of the switching valve assembly and selectively connecting thehigh-pressure side inlet to the common side outlet or the low-pressureside inlet to the common side outlet, an electromagnet installed at oneside of the switching valve housing and moving the switching valve byapplied power, and an elastic member returning the switching valve to aninitial position when power being applied to the electromagnet is cutoff.